Thee are 3 sources of resistance in a parallel circuit 2 @ 20 ohms and 1 @ 10 ohms. What is the circuits total resistance?Please explain how you got the answer, too. Thanks
2007-06-21 04:37:13 · 4 answers · asked by Athena D 1 in Science & Mathematics ➔ Engineering
Parallel resistance formula
1/Rtotal = 1/R1 + 1/R2 + 1/R3 ......
so
1/Rtotal = 1/20 + 1/20 + 1/10
1/Rtotal = 0.05 + 0.05 + 0.1
1/Rtotal = 0.2
Rtotal*0.2 = 1
Rtotal = 5 ohms
2007-06-21 04:48:48 · answer #1 · answered by jeremy s 2 · 1⤊ 0⤋
You can solve the 1/rtotal = 1/r1 + 1/r2 + 1/r3 equation, as has been done.
EEs who do this all day would look at the question and do it in their heads.
20 in paralllel with 20 is the same as 10 ohm resistor.
10 in parallel with 10 is the same as a 5 ohm resistor.
Answer 5 ohms.
Because when you put two equal value resistors in parallel you get half the resistance.
I.E:
1/rtot = 1/r + 1/r
r/rtot = 2
r = 2rtot
rtot = r/2
Don't do this on your homework, your teacher probably wants to see your working.
2007-06-21 12:30:52 · answer #2 · answered by anotherbsdparent 5 · 1⤊ 0⤋
Resistance in a parallel circuit
1/Rt = 1/R1 + 1/R2 +1/R3...
1/Rt = 1/20 + 1/20 + 1/10 Now do the math.
2007-06-21 13:09:58 · answer #3 · answered by Anonymous · 0⤊ 0⤋
The guy above is correct in: the answer, how he got it, and the fact that I could do it "in my head" in about 2 seconds.
.
2007-06-21 12:36:25 · answer #4 · answered by tlbs101 7 · 0⤊ 0⤋